Movable fulcrum for springboards



Jan. 8, 1963 Filed Aug. 10, 1961 R. C. RUDE MOVABLE FULCRUM FOR SPRINGBOARDS 2 Sheets-Sheet 1 INVENTOR.

Jan. 8, 1963 R. c. RUDE 3,

MOVABLE! FULCRUM FOR SPRINGBOARDS Filed Aug. 10, 1961 2 Sheets-Sheet 2 Unite This invention relates to supports for springboards. More particularly it provides a movable fulcrum for location between the fixed and the unsupported ends of a diving or springboard.

In the use of springboards for diving, either for pleasure diving or precision competition diving, it is normal for more than one diver to use the board. Since it is rare that each of the divers using the board will have the same weight and diving style, i.e., stride during the take-off from the board, the physical characteristics of the board are not normally optimum for each diver. This is the case with diving boards utilizing a fixed fulcrum.

It is particularly desirable that a diver match the timing of his stride with the resonant frequency of the board in order that the timing of the input of his weight to the board match the vibrational motions of the board. Since the natural or resonant frequency of the board is determined by its cantilevered geometry and inherent stiffness,

the only satisfactory way in which a board can be matched to a divers style is to alter the geometry of its mounting. This is far more convenient than to have the diver change his style.

Provisions have been made in known devices to adjust the support geometry of the diving board. But these devices are adjustable only in discrete stages and require the adjustment to be made from the ground when the board is unloaded. The device of this invention, on the other hand, is adjustable continuously over a wide range. Moreover, the adjustment may be made by the diver while he is on the board.

Generally speaking, this invention provides a movable support for an article secured, at a point remote from the location of the movable support, in a longitudinally fixed condition. The support is practiced in conjunction with a substantially horizontal load-bearing surface accommodating movement of the support. The support includes a rotatable means engaging the underside of the article to support the article. A carriage is provided for rotatably mounting the rotatable means; the carriage also includes bearing means engaging the support surface to facilitate movement of the carriage relative to the supported article. High friction inducing means fixed either to the article or to the rotatable means are provided. The invention fur. ther includes means for rotating the rotatable means to react against the friction inducing means to move the support relative to the article.

The following detailed description and explanation of a preferred embodiment of the invention is made in conjunction with the accompanying figures, wherein:

FIGURE 1 is a side elevation of a diving tower incorporating the movable support;

FIGURE 2 is an enlarged cross-sectional view of the movable fulcrum as taken along line 11-11 of FIGURE 1;

FIGURE 3 is a further enlarged cross-sectional view of the fulcrum roller and chassis rollers as taken along line Til-Til of FIGURE 2; and

FIGURE 4 is an enlarged cross-sectional view of the springboard and movable support as taken along line IV-IV of FIGURE 2, including a displacement limiting track insert on the springboard support.

The movable fulcrum provided by this invention is illustrated in conjunction with an all-metal extruded springboard illustrated more completely in my United States Patent No. 2,864,616 issued December 16, 1958.

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Referring to FIGURE 1, a diving tower 10 comprising a ladder column 11 and a frame portion 12 is installed on a deck 13 adjacent the edge of a swimming pool 14. A pair of diverging arms 15 extend upwardly from the frame members 12 to support guard rails 16. A movable fulcrum 20 is located at the upper end of the frame 12 and supports a diving board 17 which extends from the upper end of the step column 11 over the top of the fulcrum 20. The diving board has an end 18 fixed to the step portion 11 to be restrained from lateral and longitudinal movement; however, the connection at end 18 may accommodate rotational motion of that portion of the springboard 17.

As mentioned previously, the preferred form of the springboard 17 is as disclosed in US. Patent No. 2,864,616, but any conventional diving spring board is compatible with this invention. The springboard 17 may be made wholly of wood, from laminated metal portions, or from combinations of wood and metal materials.

As illustrated inFIGURE 2, the movable support apparatus 20 is mounted upon the upper extents of the frame members 12 of the board supporting and bracing tower 10. A horizontal rail or load-bearing surface 21 is provided at the upper end of each of the tower legs 12 (see FIGURE 2). The surfaces 21 preferably are coplanar and extend longitudinally of the board 17 between the arms 15 carrying the guard rails 16. The rail surfaces 21 extend from the outer surface of the tower legs 12 to parallel, oppositely disposed vertical surfaces 22 inboard of the frame 12. 1

When the movable fulcrum apparatus 20 is utilized with a low diving tower, say a one-meter tower, the rail mounting arms 15 are not present to limit the motion of the movable fulcrum 20. in such cases a rail insert 24 (See FIGURE 4) is secured to the rail surface 21 by screws 25 tapped into the tower legs 12. The rail insert plates 24 have upward flanged ends 26 to limit the amount of travel of the movable support 211. The flanges 26 are required since otherwise the wheels 35 of the chassis 311 may run 011 the pedestal 12 forming a portion of the springboard mount;

A major portion of the movable fulcrum 26 is comprised of a chassis or frame 30. The chassis 30 has parallel side walls 31 extending transversely of the rails 21. Enlarged end walls 32 join the walls 31. The top and bottom portions of the chassis 211 are open. A transverse diaphragm or partition 33 extends between each side Wall 31 adjacent the ends 32 (see FIGURE 4). The partitions 33 are depressed centrally of the side walls 31 to accommodate the rotatable fulcrum roller 50.

A pair of carriage wheels 35 are mounted to the chassis 3d and engage the rails 21 or 24. Each wheel 35 preferably comprises a circularly cylindrical roller portion 36 and an enlarged diameter or flanged end portion 37. A hole 38 is drilled axially of the wheel 35 and journals an axle 39 which is mounted between the respective ends 32 and partitions 33 of the chassis 311. The flanges 37 are positioned adjacent the outboard surface ofthe partition 33 such that when the carriage 30 is positioned onthe rails 21 or 24, the flanges 37 are adjacent the vertical guide surfaces 22. The cooperation between the flanges 37 and the surfaces 22 assures that the support of the springboard 17 is transversely of the springboard. The flanges 37 further assure that the carriage 31) does not become cocked or jammed relative to the rails 21.

As best illustrated in FIGURE 4, the wheels 35 are spaced as far apart from one another as possible consonant with minimum chassis dimensions. The side walls 31 of the body 30 are configured, as at 411, to accommodate the flange 37 andthe main weight-bearing portion 36 of the Wheels.

A rotatable fulcrum or springboard support roller 50 is mounted between the ends 32 of the chassis 30. The roller 59, in order to preserve lightness, is preferably comprised of a tubular portion 51 comprising the body of the roller. Disks or plugs 52 are fixed within each of the end portions 53 of the tubes 51. A circular hole 54 is drilled axially of the end disks 52. An axle 55 is securely fitted in each hole 54 and extends outwardly from the roller ends 53 to be journalled by a bushing 56 forcefitted into the side walls 32 of the chassis. One of the axles 56 is at least flush with the exterior surface of one of the chassis end walls 32, but the other end of axle 55 extends beyond the other chassis end wall 32 (refer to the left side of FIGURE 2).

A roller rotating means 60, in the form of a wheel, is attached to the free end of the projecting axle 5S. Preferably the wheel 60 has projecting lugs 61 spaced around its circumference to facilitate rotation of the wheel 6% and roller 50 (see FIGURE 3). In a preferred embodiment of the movable fulcrum, the outer periphery of the roller 50 is roughened by sand-blasting or by impregnation with aggregate material 62.

The springboard 17 is provided with friction-inducing means 70 in the vicinity of the movable support 20 assuring traction between the springboard 17 and the roller 50. As stated above, this invention is most preferably practiced with a springboard 17 fabricated according to the disclosures of U.S. Patent No. 2,864,616. In such a case the traction means 70 may take the form of rubber shoes, extruded in the form of channels, engaged over the free ends of the depending bulbed ribs 71 on the underside of the springboard 17. However, if the springboard 17 does not follow the construction as disclosed in Patent No. 2,864,616, the traction means 70 may be glued or bonded to the underside of the springboard. Alternatively, the drum or roller 50 may have a rubber tire bonded thereto over its length between the ends 32 of the carriage 30. The rubber shoes 70, illustrated in FIGURE 3, provide a high coeffieient of friction between the roller 50 and the under surface of the springboard 17 so that the reaction between elements 17 and 59, produced by rotation of the roller 50, results in movement of the carriage 36 along the rail 21.

During operation of the movable fulcrum as disclosed herein, particular advantage is derived from the roller drive wheel 60. A diver standing on the tower 1f) oper ates the movable fulcrum 20 by turning the whee] 64 in the desired direction by foot. The wheel 60, being of larger diameter than the roller 50, provides a high mechanical advantage so that little effort is required to properly position the fulcrum 59. It is thus a simple matter for a diver, upon discovering that the roller St is not located in a position providing a springboard natural frequency compatible with his diving style, to adjust the springing characteristics of the board 17 without descending from the tower 10.

As is readily apparent from FIGURE 1, the projection of the wheel 60 outwardly from the side of the tower leg 12 results in interference with the rail arms 15. This fact automatically limits the extent of travel of the fulcrum means 26. But the movable fulcrum means 29 provided by this invention is also adaptable to a low diving board where guard rails are not normally provided. In this type of installation, the rail insert plate 24 with the upwardly flanged ends 26 is provided as a safety feature to prevent the fulcrum SE) from rolling off the fulcrum pedestal.

Another feature of this invention is that the roller 5 is driven against the load-bearing member 17 rather than against a stationary base. This feature provides for accurate location of the carriage 30 without undue effort since the load is used to provide traction. If the carriage 30 were driven against the ground or support surface 21, then the carriage would have to work against the load and a larger input would be required to move the carriage. The feature of driving the carriage against the load-supporting article is adaptable to any installation where a load-bearing support must be moved relative to the load without removal of the load from the support. This invention utilizes the load itself to assure that the support will move as desired.

The environment selected for explanation and description of the apparatus of this invention has been merely by way of example and should not be considered as limiting the scope of this invention.

I claim:

1. A movable support for a load-bearing article comprising rotatable means engaging the underside of the article for supporting the article, body means mounting the rotatable means transversely of the article, a longitudinally oriented bearing surface for accommodating movement of the body means, bearing surface engaging means rotatably mounted to the body means for support of the body means, and means connected to the rotatable means for rotation therewith for rotating the rotatable means against the article to displace the rotatable means and its body means longitudinally of the article to change the location of article support by the rotatable means.

2. A movable support according to claim 1 including means between the rotatable means and the underside of the article for providing higher friction therebetween than between the body means and the bearing surface.

3. Adjustable position apparatus for support of an elongated load-bearing member having an underside, an end restrained from longitudinal motion, and an opposite unsupported end, the apparatus comprising a planar support surface, a rotatable roller engaged with the underside of the load bearing member at an intermediate portion of the member, the roller being disposed transversely of the member, movable means for rotatably mounting the roller, means for rollably supporting the movable means on the support surface, means for guiding the movable means longitudinally of the member during movement along the support surface, and means for rotating the roller to displace the movable means along the support surface by reaction between the roller and the member to adjust the position of roller support of the member.

4. Adjustable position apparatus for support of an elongated load-bearing member having an underside, an end restrained from longitudinal motion, and an opposite unsupported end, the apparatus comprising a planar support surface, a roller having opposite ends journalled adjacent its ends and engaged with the underside of an intermediate portion of the member transversely of the member, journal means rotatably mounting the roller adjacent its ends, means for reliably supporting the journal means on the support surface, means between the roller and the underside of the load-bearing member for providing a higher coefiicient of friction therebetween than between the journal means and the support surface, and means for rotating the roller to displace the journal means along the support surface by reaction between the roller and the member to adjust the position of roller support of the member.

5. Adjustable position apparatus for support of an elongated load-bearing member having an undersurface, an end restrained from longitudinal motion and an opposite unsupported end, the apparatus comprising a planar support surface, a rotatable roller having opposite ends and a roughened peripheral surface engaged with the underside of an intermediate portion of the member transversely of the member, traction assuring means aiiixed to the under surface of the member along the intermediate portion, shaft means secured to the roller and extending axially from the ends of the roller, means for journaliing the shaft means of the roilcr, means for reliably supporting the journal on the support surface, means for guiding the journal means longitudinally of the member during movement along the support surface, and means for rotating the roller to displace the journal means along the support surface by reaction between the roller and the member to adjust the position of roller support of the member, wherein the traction assuring means and the roughened surface of the roller assure that the roller is driven against the underside of the member.

6. An adjustable point-of-support apparatus for a substantially cantilevered member engageable against the underside of the member between the constrained end and the unsupported end, the apparatus comprising a chassis, a roller rotatably mounted to the chassis transversely of the member and having its upper periphery engaged with the underside of the member, a planar support surface for the chassis, wheel means mounted to the chassis and engaging the support surface for movement of the chassis relative to the support surface, means for guiding the chassis longitudinally of the member during motion relative to the support surface, means for rotating the roller, and means for providing a higher coeilicient of friction between the roller and the member than between the chassis and the support surface, whereby rotation of the roller and engagement thereof with the member results in movement of the roller relative to the member to adjust the location of support of the member by the roller.

7. An adjustable point-of-support apparatus for a cantilevered member engageable against the underside of the member between the fixed end and the unsupported end, the apparatus comprising a chassis, a roller, a shaft to which the roller is coaxially secured and having ends extended beyond the roller and journalled in the chassis so that the roller is disposed transversely of the member and has its upper periphery engaged with the underside of the member, a planar support surface for the chassis, wheel means mounted to the chassis and engaging the surface for movement of the chassis relative to the support surface, means for limiting the movement of the chassis relative to the support surface, means for guiding the chassis longitudinally of the member during motion relative to the support surface, means for rotating the roller, and means for providing a higher coefiicient of friction between the roller and the member than between the chassis and the support surface, whereby rotation of the roller and engagement thereof with the member results in movement of the roller relative to the member to adjust the location of the support of the member by the roller.

8. Apparatus according to claim 7 wherein the means for limiting the amount of movement of the chassis relative to the support surface comprises projection means extending upwardly from the support surface engageable with the wheel means.

9. An adjustable point-of-support apparatus for a cantilevered member engageable against the underside of the member between the end constrained from longitudinal movement and the unsupported end, the apparatus comprising a chassis, a roller rotatably mounted in the chassis transversely of the member and having its upper periphery engaged with the underside of the member, a planar support surface for the chassis, wheel means mounted to the chassis and engaging the surface so that the chassis is movable relative to the support surface, and means for rotating the roller, whereby rotation of the roller and engagement thereof with the member results in movement of the roller relative to the member to adjust the location of support of the member by the roller.

10. A movable fulcrum for a springboard having a substantially fixed end and an unsupported end in combination with a support for the springboard intermediate the ends thereof, the support providing a pair of horizontal spaced-apart parallel rails extending longitudinally of the springboard, the fulcrum comprising a frame supported on and between the rails, a pair of rollers mounted by the frame at each of a pair of opposite ends of the frame engagement with the rails, each roller being flanged peripherally at one of its ends, the roller flanges engaging the opposed sides of the rails for directing frame movement longitudinally of the springboard, a springboard fulcrum roller rotatably mounted to the frame and oriented transversely of the springboard and engaging the under surface thereof, means secured to the underside of the springboard in the vicinity of the support for providing high friction between the springboard and the fulcrum, and means accessible to a person on the springboard for rotating the fulcrum roller, whereby the frame is driven along the rails and the position of the fulcrum is adjustable longitudinally of the springboard by rotation of the fulcrum roller against the friction providing means.

11. A movable fulcrum according to claim 10 wherein the springboard includes longitudinal parallel downward projections, the means for providing high friction between the springboard and the fulcrum comprises shoe means engaged with the projection means in the vicinity of the support, and the circumference of the fulcrum roller is roughened for positive engagement with the shoe means.

12. A movable fulcrum according to claim 10 wherein the means for rotating the fulcrum roller comprises a wheel having radial lugs and mounted coaxially of the fulcrum roller and positioned outwardly of a longitudinal side of the springboard.

References Cited in the file of this patent UNITED STATES PATENTS 2,032,574 Handley Mar. 3, 1936 

1. A MOVABLE SUPPORT FOR A LOAD-BEARING ARTICLE COMPRISING ROTATABLE MEANS ENGAGING THE UNDERSIDE OF THE ARTICLE FOR SUPPORTING THE ARTICLE, BODY MEANS MOUNTING THE ROTATABLE MEANS TRANSVERSELY OF THE ARTICLE, A LONGITUDINALLY ORIENTED BEARING SURFACE FOR ACCOMMODATING MOVEMENT OF THE BODY MEANS, BEARING SURFACE ENGAGING MEANS ROTATABLY MOUNTED TO THE BODY MEANS FOR SUPPORT OF THE BODY MEANS, AND MEANS CONNECTED TO THE ROTATABLE MEANS FOR ROTATION THEREWITH FOR ROTATING THE ROTATABLE MEANS AGAINST THE ARTICLE TO DISPLACE THE ROTATABLE MEANS AND ITS BODY MEANS LONGITUDINALLY OF THE ARTICLE TO CHANGE THE LOCATION OF ARTICLE SUPPORT BY THE ROTATABLE MEANS. 